Get files access permissions using stat() in C

I just started learning linux/C, i just want to show the names of all the files of the directories given in argument, and their access permissions by using stat() which causes some problems. It actually shows the correct name/mode of all the files included in the current directory, but for the other directories given in argument, it does give the right name but the same st_mode for all the files…

here’s my code:

#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/types.h>
#include <dirent.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>

int main(int argc, char *argv[]) {
    printf("Hello, world!n");
    int status;
    struct stat sbuf;
    DIR *dirp;
    struct dirent *dp;

    dp = (struct dirent*) malloc(sizeof(struct dirent));


    for (int i=1; i<argc; i++){

        dirp = opendir(argv[i]);
        if (dirp == NULL){/*perror("Argument invalide");*/printf("Argument %d invalid", i); exit(1);}   

        printf("nnOpening %sn", argv[i]);
    do{

        dp = readdir(dirp);

        if (dp != NULL && strcmp(dp->d_name,".") && strcmp(dp->d_name, "..")) { 
            status = stat(dp->d_name,&sbuf);
            printf("The file is %s tMode :%on", dp->d_name, (sbuf.st_mode & 0777));
        }

    } while (dp != NULL);

    closedir(dirp);
    }
    return 0;
}

for example I did try this : gcc -o test main.c then ./test . ..

And here’s the result !

Opening .
The file is c.txt   Mode :644
The file is d.txt   Mode :644
The file is xxxx.txt    Mode :777
The file is test    Mode :755


Opening ..
The file is a.txt   Mode :755
The file is b.txt   Mode :755
The file is dossier     Mode :755
The file is main    Mode :755
The file is main.c  Mode :755
The file is test    Mode :755

As you can see, all the files of the ” .. ” directory have the same Mode, which is completely wrong… I did try with full paths and different directories, same problem.

Answer

Well, stat isn’t giving you the file information because readdir gives you the file name, not the path. Try something like this to build up the path so you can actually call stat.

char *path = malloc(strlen(dp->d_name) + strlen(argv[i]) + 2);
stpcpy(stpcpy(stpcpy(path, argv[i]), "/"), dp->d_name);
status = stat(path,&sbuf);
free(path);

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Answer